Organ affected: lungs

Common questions about lung IgG4-RD

After learning that IgG4-related disease can affect the lungs, many people have practical questions. Some worry because they have a cough or asthma-like symptoms. Others feel well but have lung changes on a scan. Some are starting treatment and want to understand steroids, B-cell medicines, infection risk, oxygen, or follow-up testing.

The answers to these questions are general teaching points. Your own plan should come from your care team, because lung IgG4-RD can look different from person to person.

1. Does lung IgG4-RD always cause symptoms?

No. Lung IgG4-RD can cause cough, wheeze, shortness of breath, chest discomfort, or drops in the level of oxygen in the blood, but some people have no lung symptoms at all. In some cases, lung findings are discovered by accident when a CT scan is done for another reason.

This can feel surprising. We often expect lung disease to announce itself clearly, but IgG4-RD can be quiet. That is why doctors do not rely only on how you feel. They may also look at CT scans, pulmonary function tests, walking tests, the levels of oxygen in the blood, and the degree of disease activity (if any) in organs beyond the lung.

The goal is to understand whether the lung finding is active, stable, or fibrotic, and whether it is affecting breathing now.

2. If I have asthma or wheezing, does that mean IgG4-RD is in my lungs?

Not always. Asthma is common, and a person with IgG4-RD can also have ordinary asthma. Wheezing can also come from reflux, post-nasal drip, COPD, infection, allergies, or airway inflammation.

Still, IgG4-RD can sometimes affect the airways or lung tissue in ways that feel like asthma. If symptoms do not behave like typical asthma, or if they improve when systemic IgG4-RD treatment controls inflammation, your team may look more closely at whether IgG4-RD is contributing.

The practical question is not only “Is this asthma?” It is also, “Are my symptoms, scans, breathing tests, and treatment response telling the same story?”

3. Do I need regular lung testing if I have IgG4-RD but no lung symptoms?

There is no one-size-fits-all screening plan for every person with IgG4-RD. If you have no lung symptoms and no known lung involvement, your doctor may not order repeated lung tests on a fixed schedule.

That said, your team may have a lower threshold to check the lungs if symptoms appear, if another organ becomes active, or if earlier imaging showed nodules or other findings. Once IgG4-RD has been recognized as affecting the lung, any subsequent flare is likely to involve the lung again, as well. A chest X-ray may be a first step for new symptoms, while CT gives more detail when needed.

Ask your clinician if there are clear signals that might trigger lung testing for you. Possible signals might include new cough, wheeze, shortness of breath, chest pain, falling exercise tolerance, or oxygen changes.

4. If my lung nodule is stable, do I still need treatment?

Not necessarily. A stable lung nodule or stable lung change may be watched rather than treated right away, especially if breathing tests are steady and there are no concerning symptoms.

Treatment is more likely when the team sees active inflammation, growth over time, more difficulty with breathing, decreases in the amount of oxygen in the blood (measured by a simple probe on the finger: a “pulse oximeter”), narrowing or thickening of airways seen on imaging, or obviously active IgG4-RD in other organs. Your radiology report may also suggest whether and when a nodule should be re-imaged.

Stable does not mean ignored. It means the team has not seen signs that immediate treatment is needed. The key is having a clear follow-up plan: what will be checked, when it will be checked, and what change would lead to action.

5. How does my team decide between monitoring and treatment?

Your team looks at the whole picture. They ask whether the lung disease is active, stable, fibrotic, or mixed. They also look at symptoms, CT changes, pulmonary function.

If inflammation is active and likely to cause harm, treatment may be recommended. If the finding looks old, fibrotic (scarred), and stable, monitoring may be safer. Sometimes treatment is chosen because another organ, such as the kidneys, pancreas, or blood vessels, needs systemic (whole-body) treatment. In those settings, the lungs may benefit from treatment, too.

This is why management is personalized. The best plan is the one that protects your lungs, considers the overall disease activity status, and avoids unnecessary treatment risk.

6. Will steroids or B-cell treatment help lung IgG4-RD?

They may help when the lung problem is driven by active inflammation. Steroids such as prednisone can work quickly, but side effects can include sleep problems, mood changes, weight gain, blood sugar changes, bone thinning, and infection risk.

B-cell treatments quiet part of the immune system involved in IgG4-RD. Inebilizumab, a CD19-directed B-cell treatment, is FDA-approved for adults with IgG4-RD. Rituximab has been used off-label in IgG4-RD. Other therapies that target B-cells in other ways are also being developed. Treatment choice depends on lung function, other organs involved, prior steroid side effects, infection risk, vaccine timing, and patient preferences. ^1-2

If the main lung issue relates more to fibrosis than to active inflammation, treatment may focus on preventing further damage and supporting breathing.

7. What can I do to keep my lungs as healthy as possible?

You cannot control every part of IgG4-RD, but you can support your lungs. Ask about vaccines for respiratory infections, including flu, COVID-19, pneumococcal, RSV, and shingles when appropriate. The timing of these vaccines matters, especially before B-cell-depleting treatment.

Treat other lung conditions, such as asthma, COPD, reflux, and post-nasal drip. Avoid smoke exposure and DO NOT SMOKE yourself. Stay active within your limits. If breathing is reduced, pulmonary rehabilitation can help you build strength and confidence.

Supplemental oxygen may be needed if levels drop often during activity but it is unusual for patients to require this purely because of IgG4-related lung disease. Usually there are other contributing factors.

These steps do not replace IgG4-RD treatment when treatment is needed. They help reduce avoidable strain on the lungs.

8. When should I call my care team?

Call your care team if you have new or worsening shortness of breath, chest pain, fever, worsening cough, coughing up blood, new oxygen drops, fainting, or symptoms that feel sudden or severe. Seek urgent care right away for severe breathing trouble, severe chest pain, blue lips, confusion, or oxygen levels that are dangerously low for you.

Also call if symptoms return during or after a steroid taper, after an infusion, or after an infection. A flare can look like worsening cough, wheeze, shortness of breath, drops in oxygen levels, or new CT changes. But infection, asthma, COPD, heart disease, blood clots, and medication side effects can look similar.

Your flare plan should tell you who to call, what symptoms matter, and what information to share.

References

1. Stone JH, Khosroshahi A, Zhang W, et al. Inebilizumab for treatment of IgG4-related disease. New England Journal of Medicine. 2024. doi:10.1056/NEJMoa2409712. https://www.nejm.org/doi/full/10.1056/NEJMoa2409712

2. U.S. Food and Drug Administration. UPLIZNA® (inebilizumab-cdon) prescribing information. 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761142s004lbl.pdf

3. Overfield C, Doffinger R, Jeyaratnam J, et al. Pulmonary manifestations, treatments and outcomes of IgG4-related disease: a systematic literature review. Rheumatology International. 2024;44:1875–1886. doi:10.1007/s00296-024-05611-7. https://link.springer.com/article/10.1007/s00296-024-05611-7

4. American College of Rheumatology. IgG4-related disease patient information. 2025. https://rheumatology.org/patients/igg4-related-disease-igg4-rd

5. Cleveland Clinic. IgG4-related disease. 2026. https://my.clevelandclinic.org/health/diseases/igg4-disease